Discord MCP

Reagir a mensagem

add_reaction

Idempotent

Add or remove an emoji reaction on a Discord message using unicode or custom emoji, enabling an agent to acknowledge or respond in conversations.

Instructions

Adiciona (ou remove, com remove=true) uma reacao da conta em uma mensagem. emoji aceita unicode ("👍") ou emoji personalizado no formato nome:id.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "channelId": "<channelId>",
      "messageId": "<messageId>",
      "emoji": "<emoji>"
    },
    "name": "add_reaction"
  }
}

Input Schema

Name	Required	Description
`emoji`	Yes	Emoji unicode ou nome:id.
`format`	No	text (padrao) devolve texto compacto; json devolve o objeto bruto.
`remove`	No	Remover a reacao em vez de adicionar. Padrao false.
`channelId`	Yes	Canal (id numerico do Discord).
`messageId`	Yes	Mensagem (id numerico do Discord).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Oct 20, 2026

TDQS

A3.6/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the add/remove toggle and emoji format, but both are restated from the schema; no auth, rate-limit, or return behavior is disclosed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tightly written sentences; the primary action is front-loaded and the remove=true qualifier is appended without wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple single-target action, the description plus rich annotations and full schema coverage is nearly sufficient. Minor gaps (rate-limit or permission behavior on an openWorld mutation) remain, but the include the dual mode and format options.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters (including remove and format) are already documented in the schema. The description's emoji-format note duplicates the schema's own emoji description, adding no meaning beyond structured data; baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('adiciona/remove uma reacao... em uma mensagem') and clarifies the dual add/remove mode. Clear enough to distinguish from edit_message or send_message, though it doesn't name any sibling explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The remove=true flag gives conditional usage for the inverse operation, which is genuine guidance. However there is no explicit when-to-use vs alternatives context or prerequisites (e.g., needing access to the channel).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.